<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>3.当前输入框高亮显示</title>
  </head>
  <style>
    body,
    form,
    h2,
    p,
    input {
      margin: 0;
      padding: 0;
    }
    body {
      color: #4f4f4f;
      font: 14px/1.5 \5fae\8f6f\96c5\9ed1;
    }
    form {
      width: 400px;
      background: #fef4eb;
      border: 2px solid skyblue;
      padding-bottom: 10px;
      overflow: hidden;
      zoom: 1;
      margin: 10px auto;
    }
    form h2 {
      color: skyblue;
      font-size: 16px;
      color: #000;
      background: skyblue;
      border-bottom: 2px solid skyblue;
      padding: 5px 10px;
    }
    form p {
      float: left;
      clear: both;
      width: 100%;
      height: 31px;
      margin-top: 10px;
      line-height: 31px;
    }
    form label,
    form input {
      float: left;
    }
    form label {
      width: 100px;
      height: 31px;
      text-align: right;
    }
    form input {
      border: 0;
      font-family: \5fae\8f6f\96c5\9ed1;
      background: url(img/input.png) no-repeat;
    }
    form .f-text,
    form .f-text-high {
      width: 203px;
      height: 31px;
      padding-left: 5px;
      line-height: 31px;
    }
    form .f-text-high {
      background-position: 0 -31px;
    }
    form .f-btn {
      color: #fff;
      width: 104px;
      height: 31px;
      cursor: pointer;
      font-size: 16px;
      background: red;
      line-height: 31px;
      border-radius: 5px;
    }
  </style>
  <body>
    <form>
      <h2>用户登录</h2>
      <p><label>用户名：</label><input class="f-text" type="text" /></p>
      <p><label>密码：</label><input class="f-text" type="password" /></p>
      <p><label></label><input class="f-btn" type="button" value="登 录" /></p>
    </form>
  </body>
  <script type="text/javascript">
    var aInput = document.getElementsByTagName("input");
    var i = 0;
    for (i = 0; i < aInput.length - 1; i++) {
      aInput[i].onfocus = function () {
        this.className = "f-text-high";
      };
      aInput[i].onblur = function () {
        this.className = "f-text";
      };
    }
  </script>
</html>
